DE102013205218A1 - Method for preparing an acceleration process of an internal combustion engine - Google Patents

Abstract

The invention relates to a method for preparing an acceleration process of a motor vehicle, wherein at least one wheel of the motor vehicle is driven by an internal combustion engine, a first variable, which indicates the acceleration process, changing a first quantity influencing a drive torque to the at least one wheel is that the drive torque is increased to the at least one wheel (103), and a second variable influencing the drive torque to the at least one wheel is changed such that the drive torque is reduced to the at least one wheel (103), and wherein to a second event triggering the acceleration process, the second quantity influencing the drive torque to the at least one wheel is changed such that the drive torque is increased to the at least one wheel (106).

Description

The present invention relates to a method for preparing an acceleration operation of an internal combustion engine.

State of the art

In motor vehicles, a variety of systems are used, which make the driving more comfortable and reduce the fuel consumption of the motor vehicle. For example, automatic transmissions or semi-automatic transmissions, in particular dual-clutch transmissions, enable fast and automated switching operations. Thus, a reduced fuel consumption can be achieved by the transmission automatically switches early in a higher gear. By means of a turbocharger a maximum engine torque and a maximum engine power of the internal combustion engine can be achieved and offer the driver a comfortable and sporty driving experience.

However, if the driver wants to accelerate spontaneously and wishes to increase the engine torque rapidly, delayed response of said systems may occur. Under certain circumstances, the system first switches to a lower gear, because, for example, a boost pressure must be increased in order to ensure optimum acceleration behavior.

Especially for sports vehicles, the acceleration behavior is an essential part of the driving experience and is an important factor for a purchasing decision by potential buyers. A delayed response and a non-optimal acceleration behavior are contrary to this sporty driving behavior.

For example, after a construction site or a speed limited area on a highway, a driver may perform a spontaneous acceleration operation to quickly return to a high speed. In overhull operations on rural roads, it is of great importance that the motor vehicle has an optimal acceleration behavior to complete the Überhohlvorgang as quickly as possible. However, if a delayed response, the overtaking is unnecessarily prolonged, which can pose a major security risk, both for the occupants of the overtaking motor vehicle and the vehicle to overtake and possible oncoming traffic represents.

It is therefore desirable to provide a way to reduce a delayed response during acceleration and to ensure optimum acceleration behavior of a motor vehicle.

Disclosure of the invention

According to the invention, a method for preparing an acceleration process of a motor vehicle, wherein at least one wheel of the motor vehicle is driven by an internal combustion engine, with the features of claim 1 is proposed. Advantageous embodiments are the subject of the dependent claims and the following description.

Advantages of the invention

By detecting a first event indicative of an imminent acceleration event, the engine and other parts involved in the acceleration operation, such as turbocharger and / or transmission, can be prepared in time for the acceleration process and necessary actions can be initiated , A first variable influencing a drive torque on the at least one wheel is changed in such a way to the first event indicating the acceleration process that an optimal acceleration behavior is achieved.

As a variable influencing the drive torque on the at least one wheel size all the adjustable sizes of the motor vehicle, which influence the drive torque to the wheels and thus ultimately the speed of the motor vehicle, can be selected. The variables can act on all components of the motor vehicle, for example on the internal combustion engine, the transmission, the turbocharger, a clutch, an electric generator or a drive train.

Thus, the first size can be set early on values that allow optimal acceleration behavior. In this case, the first size is expediently changed only to the extent that structural protection conditions permit, for example a catalyst temperature, a turbine temperature of the turbocharger, a maximum charge pressure.

However, since the acceleration process for the first event is not yet taking place, a second variable influencing a drive torque on the at least one wheel is initially changed in order to counteract the change in the first variable. The drive torque to the wheels of the motor vehicle is thus initially kept approximately constant as long as the acceleration process is not yet triggered. By changing the First, the internal combustion engine and the other components of the motor vehicle involved in the acceleration process are prepared for the acceleration process. By changing the second size is ensured that the current speed of the motor vehicle or the instantaneous drive torque is initially maintained on the wheels of the motor vehicle.

If a second event takes place, which finally triggers the acceleration process, the second variable is changed in such a way that the change of the second variable in the course of the first event is at least partially reversed. The change of the first size is now effective and it is immediately the optimal acceleration behavior of the motor vehicle available.

By the method according to the invention a delayed response is avoided in a simple manner, without expensive components or large cost. Since expediently the first and the second variable are changed shortly before the acceleration process, the internal combustion engine and the remaining components of the motor vehicle are operated only for a short time with the changed values of the first and second variables. Thus, the fuel consumption is not unnecessarily increased.

The inventive method is particularly suitable for use in an internal combustion engine in combination with a turbocharger, a compressor and / or an automatic transmission or semi-automatic transmission. However, the method according to the invention should not be limited to this specific embodiment, but is suitable for any type of motor vehicle.

Preferably, an engaged gear is changed to the first and / or second event and a suitable gear is engaged. This is particularly suitable for motor vehicles with automatic transmission or semi-automatic transmission. For example, after the first event, first in a lower gear and after the second event in a higher gear. The automatic switching process during an acceleration process can thus be optimized.

Advantageously, one or more engine variables, in particular desired values of one or more engine variables, are changed as the first variable. In particular, a cylinder filling, in particular the cylinder filling with air, is increased to a value which is greater than a normal value for the normal operation of the internal combustion engine. For example, a target value of the cylinder charge may be determined as a difference to this normal value or as an absolute value. The cylinder charge can be influenced for example by changes in a camshaft phasing, a camshaft stroke adjustment, closing times of valves and / or valves in an intake manifold and / or in an exhaust pipe.

Furthermore, a turbocharger speed, an exhaust gas mass flow, an exhaust gas enthalpy, a pressure ratio across a throttle valve of the internal combustion engine, and / or the position of a control flap of the compressor can be changed as a first variable. The exhaust gas mass flow can be changed, for example, by means of an exhaust gas recirculation valve with a valve flap. This ensures in particular that the boost pressure of the turbocharger is brought to an optimum value. The boost pressure may be further varied, for example, by a pressure ratio across a turbine of the turbocharger or by an exhaust gas temperature.

Preferably, the first size is changed depending on one or more factors. The factors may include, for example, external conditions and current thermodynamic parameters such as an ambient pressure, an ambient temperature, an intake air temperature and / or a component protection temperature, in particular an intake air temperature, the catalyst temperature and / or the turbine temperature of the turbocharger. The factors may also relate to the current, current driving behavior of the motor vehicle in order to ensure the optimal acceleration behavior starting from the current movement of the motor vehicle. Thereby, e.g. a vehicle speed, an engine speed of the internal combustion engine, a position of an accelerator pedal, an engaged gear, a maximum possible current engine torque of the internal combustion engine, a maximum possible, current acceleration and / or a maximum turbocharger speed are taken into account as factors. The factors can also be specified by the driver. For example, the driver may set values manually, such as a maximum value, a minimum value, or the setpoint value of engine sizes. The setting can be done for example via an on-board computer or a special actuator. The driver may also specify a driving mode, e.g. a normal, sport or fuel economy mode.

Preferably, a firing angle and / or the position of the throttle valve are changed as a second size. In particular, the ignition angle is retarded. Thus, an ignition time or an air ratio of the fuel-air mixture is changed. Alternatively or additionally, an injection of individual cylinders can be prevented and the internal combustion engine can only be operated in a partial engine operation. Furthermore, also sizes of others Components of the motor vehicle to be changed as a second size. For example, the coupling can be at least partially opened. Also, an electric machine can be operated as a generator. Power generated by the electric machine can be temporarily stored.

In a particularly advantageous embodiment of the invention, a first actuating element is actuated as a first event, for example by the driver. The first actuating element can be designed, for example, as a switch, a lever, a knob or another MMI element in the dashboard area or on the steering wheel. If the driver knows that he wants to accelerate in a short time, for example shortly before the end of a speed limit, before the end of a construction site or before an overhaul, he operates the first actuator. The motor vehicle prepares automatically for the upcoming acceleration process.

A delayed response is thus avoided and ensures a sporty driving. In particular, the operation of a special actuator, thereby achieving a better acceleration performance, increases driving pleasure and gives the driver a sporty driving feel.

Especially in overtaking the security can be increased. If the driver starts an overtaking process and a delayed response occurs, the overtaking process is unnecessarily prolonged. By means of the method according to the invention, the driver is already at the beginning of the overtaking process the best possible acceleration of the motor vehicle available and overtaking can be completed as quickly as possible.

Alternatively or additionally, the first event can also be detected automatically by the motor vehicle. For example, the road can be monitored automatically by means of a video surveillance system which recognizes traffic signs. The recognition of a sign indicating an imminent acceleration process, such as the detection of a particular road sign, e.g. End of the speed limit, end of the construction site, end of the hollow prohibition, forms the first event.

Advantageously, several options are available by means of the first actuating element. The driver can select, for example, which size or sizes of the components of the motor vehicle should be changed as the first size. In particular, a multi-stage preparation of the acceleration process is made possible. If the driver selects a first stage, the values of the first and second variables are changed, for example, but the same gear remains engaged or the driver can switch to another gear himself. If the driver selects a second stage, the optimum gear is additionally selected and inserted automatically. For this multi-stage preparation of the acceleration process, the first actuating element can be designed in particular as a toggle switch with two flip-flops or as two different switches or buttons. It is also conceivable that the driver selects the first stage by operating the first actuating element once and by operating the first actuating element twice within a short time interval, e.g. within half or one second, the second stage selects.

Preferably, the change in the position of the accelerator pedal forms the second event. In particular, the achievement of a kickdown position or a maximum stop of the accelerator pedal may form the second event.

Preferably, the changes of the first and second sizes are reversed if the second event does not occur within a predetermined time interval after the first event. This ensures that the internal combustion engine and the remaining components of the motor vehicle are not operated over a longer period of time with unfavorable, not optimally adjusted variables, if ultimately no acceleration process takes place. It is advisable to store the values of the first and second size before they are changed after the first event. The predetermined time interval may include, for example, one, five or ten seconds. Thus, a delayed response is avoided without unnecessarily increasing fuel consumption.

An arithmetic unit according to the invention, e.g. a control device of a motor vehicle is, in particular programmatically, configured to perform a method according to the invention.

The implementation of the method in the form of software is also advantageous, since this causes particularly low costs, in particular if an executing control device is still used for further tasks and therefore exists anyway. Suitable data carriers for providing the computer program are, in particular, floppy disks, hard disks, flash memories, EEPROMs, CD-ROMs, DVDs and the like. It is also possible to download a program via computer networks (Internet, intranet, etc.).

Further advantages and embodiments of the invention will become apparent from the description and the accompanying drawings.

It is understood that the features mentioned above and those yet to be explained below can be used not only in the particular combination indicated, but also in other combinations or in isolation, without departing from the scope of the present invention.

The invention is illustrated schematically with reference to an embodiment in the drawing and will be described in detail below with reference to the drawing.

Brief description of the drawings

1 shows a schematic representation of an internal combustion engine with a control unit which is adapted to perform an embodiment of a method according to the invention.

2 Schamtisch shows a preferred embodiment of a method according to the invention as a block diagram.

Embodiment (s) of the invention

In 1 is an internal combustion engine 1 shown in which a piston 2 in a cylinder 3 can be moved up and down. The piston becomes a crankshaft 14 placed in a rotational movement over which ultimately at least one wheel of the motor vehicle is driven with a drive torque. The crankshaft is connected to a drive train, which usually has a gearbox, a clutch, brakes, an electric machine, etc.

The cylinder 3 is with a combustion chamber 4 provided to the over valves 5 an intake pipe 6 and an exhaust pipe 7 are connected. The intake pipe 6 is with the exhaust pipe 7 via an exhaust gas recirculation valve 13 with a valve flap 13a connected as an actuator for external exhaust gas recirculation. The valve flap 13a is with a signal EGR from a control unit (ECU) 16 controllable. Furthermore, with the combustion chamber 4 a controllable with a signal TI injector 8th and a triggerable with a signal ZW spark plug 9 connected. The internal combustion engine 1 according to 1 is based on the spark ignition process. It should be understood, however, that the invention is not dependent on the method of ignition of the internal combustion engine and is well suited for self-ignition internal combustion engines.

In the intake pipe 6 are a boost pressure sensor 18 outputting a signal LD indicative of the boost pressure in the intake manifold, and a throttle valve 12 , whose rotational position is adjustable by means of a signal DK housed. The intake pipe 6 is still with an air mass sensor 10 and the exhaust pipe 7 with a lambda sensor 11 Mistake. The air mass sensor 10 measures the air mass of the intake pipe 6 supplied fresh air and generated in response to a signal LM. The lambda sensor 11 measures the oxygen content of the exhaust gas in the exhaust pipe 7 and generates a signal lambda (λ) in response thereto. The lambda probe 11 is an exhaust system (not shown) including a catalyst, for example. 3-way catalyst, followed by.

Between the air mass sensor 10 and the throttle 12 is in this example in internal combustion engines with turbocharging the compressor 19 a turbocharger arranged. The compressor 19 , in particular a control flap of the compressor 19 , is controllable by means of a signal KP. In internal combustion engines with turbocharging is after the lambda probe 11 the turbine 20 the turbocharger installed. The turbine 20 , in particular a speed of the turbine 20 , is controllable by means of a signal TR.

Furthermore, the control unit 16 connected to an accelerator pedal sensor which generates a signal FP, the position of a driver operable accelerator pedal 17 and thus indicates the engine torque requested by the driver.

Furthermore, actuator is 15 available. The actuator 15 is formed in this example as a driver-operable button in a dashboard region of the motor vehicle. When the button is pressed 15 a signal TB is sent to the control unit 16 transfer.

The control unit 16 is to set up a preferred embodiment of a method according to the invention, which in 2 is shown as a block diagram to perform.

In step 101 a motor vehicle is operated in a normal mode. The current values of variables of the components of the motor vehicle, such as engine sizes or sizes of the turbocharger, thereby represent normal values. The motor vehicle moves at approximately constant speed, ie an approximately constant drive torque on the at least one wheel and performs no significant acceleration processes.

In step 102 a first event indicative of an acceleration event is registered. In this example, the driver operates the button 15 , For example, the driver is on a country road and would like to overtake a motor vehicle driving in front of him. The driver recognizes that in the near future no oncoming traffic meets and an overheating process is possible and presses the button 15 ,

In step 103 saves the controller 16 First, the current values of a first and second influencing the drive torque on the at least one wheel size. In this example, a target value of a cylinder fill forms the first size. The control unit 16 increases the target value to a value that allows an increase in the engine torque and ultimately the drive torque to the at least one wheel. The control unit 16 calculates the correspondingly changed target value as a function of an intake air temperature, an ambient temperature, an ambient pressure and a driving mode set by the driver.

At the same time the control unit changes 16 as a second size a firing angle and performs, for example, a retardation. Furthermore, the controller changes 16 a position of the throttle 12 as a second variable and, if necessary, prevents injection of individual cylinders 3 of the internal combustion engine 1 , which results in a reduction of the engine torque and ultimately the drive torque on the at least one wheel. The increase and decrease of the drive torque to the at least one wheel counteract each other, so that of the internal combustion engine 1 Motor torque output to a drive shaft and thus the drive torque to the at least one wheel remains substantially the same.

Preferably, the changes in the first and the second size are signaled to the driver, for example on a display device designed as an HMI element (human-machine interface), for example a display, a light signal or the like. Thus, the driver can determine whether an improved acceleration behavior is actually to be expected when the accelerator pedal is actuated, and he can adapt his driving behavior accordingly.

In step 104 checks the control unit 16 whether a second event triggering the acceleration takes place within a time interval of, for example, five seconds. In this example represents a change in the position of the accelerator pedal 17 in the sense that the driver gives more gas, the second event. Is done within the time interval, no change in the position of the accelerator pedal 17 or the position changes such that the driver gives less gas and / or the driver presses the brake, this means that the driver does not want to perform an acceleration operation. In this case, the controller makes 16 in step 105 reverse the change of the first and second sizes and change the first and second size back to the values set at the beginning of step 103 were saved. The aforementioned signaling would be canceled.

If the driver gives more throttle within the time interval, he would like to accelerate. In this example of an overhaul operation, the driver now accelerates to disengage and begin the overhaul process. In step 106 makes the controller 16 the change of the second size, in step 103 reversed. The engine torque of the internal combustion engine is increased due to the changed first size, correspondingly increases the drive torque on at least one wheel and the motor vehicle undergoes an optimal acceleration process.

Once the acceleration process in step 107 is finished and the speed of the motor vehicle is no longer increased, the motor vehicle is operated again in the normal mode and the method returns to step 101 back, indicated by reference numerals 108 ,

Claims (13)

Method for preparing an acceleration process of a motor vehicle, wherein at least one wheel of the motor vehicle is driven by an internal combustion engine ( 1 ), wherein a first, the acceleration process indicating event ( 102 ) - a first a drive torque on the at least one wheel influencing variable is changed such that the drive torque is increased to the at least one wheel ( 103 ), and - a second variable influencing the drive torque on the at least one wheel is changed in such a way that the drive torque is reduced to the at least one wheel ( 103 ), and on a second, the acceleration process triggering event out - the second the drive torque to the at least one wheel influencing variable is changed such that the drive torque is increased to the at least one wheel ( 106 ). Method according to claim 1, wherein the first event indicating the acceleration process ( 102 ) and / or on the second event triggering the acceleration process, an engaged gear is changed. A method according to claim 1 or 2, wherein one of a motor torque of the internal combustion engine ( 1 ) influencing variable is changed as the first and / or the second the drive torque to the at least one wheel influencing variable ( 103 ). Method according to one of the preceding claims, wherein - a cylinder filling in a combustion chamber ( 4 ) of a cylinder ( 3 ) of the internal combustion engine ( 1 ), - a pressure ratio above a throttle valve ( 12 ) of the internal combustion engine ( 1 ), - a turbocharger speed of a turbocharger ( 20 ) of the internal combustion engine ( 1 ), - an exhaust gas mass flow in an exhaust pipe ( 7 ) of the internal combustion engine ( 1 ), - an exhaust enthalpy and / or - a position of a control flap of a compressor ( 19 ) of the internal combustion engine ( 1 ) as the first variable influencing the drive torque on the at least one wheel ( 103 ). A method according to any one of the preceding claims, wherein the first variable influencing the drive torque on the at least one wheel is varied in accordance with at least one of: an ambient pressure, an ambient temperature, an intake air temperature, a vehicle speed, a position of a vehicle Accelerator pedal ( 17 ), - a maximum possible, current engine torque of the internal combustion engine ( 1 ), - a maximum possible, current acceleration, - an engine speed of the internal combustion engine ( 1 ), - an engaged gear, - a component protection temperature, - a maximum turbocharger speed of a turbocharger ( 20 ) of the internal combustion engine ( 1 ), - a driving mode and / or - a value set by a driver. Method according to one of the preceding claims, wherein an ignition angle, a position of the throttle valve ( 12 ), an injection of a cylinder ( 3 ) of the internal combustion engine ( 1 ), a torque taken off by an electric motor and / or a clutch position are changed as the second variable influencing the drive torque on the at least one wheel ( 103 ). Method according to one of the preceding claims, wherein an actuation of an actuating element ( 15 ) is the first event indicating an acceleration process ( 102 ). Method according to one of the preceding claims, wherein a change of a position of the accelerator pedal ( 17 ) is the second, the acceleration process triggering event. Method according to one of the preceding claims, wherein the changes of the first and the second the driving torque on the at least one wheel influencing variable are reversed ( 105 ), when the second event triggering the acceleration does not occur within a predetermined time interval after the first event indicative of the acceleration operation. Method according to one of the preceding claims, wherein the change of the first influencing a drive torque on the at least one wheel on the first, the acceleration process indicative event ( 102 ) and / or the change of the second variable influencing the drive torque on the at least one wheel to the first event indicating the acceleration process ( 102 ) is signaled via a display device. Arithmetic unit ( 16 ), which is adapted to perform a method according to any one of the preceding claims. Computer program with program code means comprising a computer unit ( 16 ) to perform a method according to any one of claims 1 to 10, when on the computing unit ( 16 ), in particular according to claim 11, are executed. A machine-readable storage medium having a computer program stored thereon according to claim 12.

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